Sardinia as a 100% renewable power system: A frequency stability study

Abstract

This paper investigates a real complex power system supplied by a 100% renewable generation, focusing on the primary frequency regulation. The grid and the power production park are represented by means of an electro-mechanical model in a free open-source environment. The lack of synchronous generators in the grid, due to the conventional power plants shutdowns, requires higher performances from renewable power plants (RPPs) in terms of synchronization and inertial response. Doubly fed induction generators (DFIGs) are identified as the promising power plants able to lessen inertial issues. DFIG system control is investigated in the present paper, according to the recent studies in the literature, implementing a new strategy of control in case of avoiding maximum power point tracker (MPPT) operation. The 100% renewable 112-bus Sardinia islanded power system is the case study of this paper. Four scenarios were selected to show the primary frequency response in the most critical under and upper frequency events among the year. The simulations revealed that the most severe frequency nadir in the simulation reached a decrease of 0.37 Hz. DFIGs control system appeared robust in terms of inertial response and capability of reaching new stable operating point.